Albacora Manifold - The Deepest Subsea Manifold Installed To Date

Abstract

Abstract The installation of the two Albacora Manifolds, made them the deepest Subsea Production Manifolds ever installed. These Manifolds are designed for installation and operation at 1000 meters water depth and were installed at 620 meters in the Aibacora field, Campos Basin offshore Brazil, on December '95 and April '96. Each Manifold is connected to eight satellite wells via a Vertical Flowline Comection System. The export of the crude to the FPS is made via an 10" flexible line along with a 4" line for production test and another 10" service line for pigging purposes; gas lift is made through a 4" line. All these flexible lines are also connected via a Vertical Connection System. These manifolds are comprised of four guidelineless retrievable Valve and Choke Modules that include all isolation gate valves and subsea chokes, The controls are made by a Multiplex Control System, The control pods can be installed or retrieved using guidelineless techniques. The Control System is able to function and acquire data from the Marufold valves as well as the satellite Trees valves. The Marufolds consist of two structures, a sub base that is used as J shallow foundation and the Manifold Structure that houses the Valve and Choke Modules, Control Systems Pods. Vertical Connection Systems and all the plumbing, The total weight of the whole system is 450 tons. Introduction Three economic reasons can be highlighted for the selection of a Subsea Production Manifold for the development of Albacora field: 1 - Minimize the utilization of flowlines and production risers; 2 - Simplify FPS configuration by reducing [he number of risers hook up's; 3- Anticipate production. As long as paraffin or wax is not expected to be a problem in relatively short lengths of flowlines from the satellite wells to the Manifold and there is no need for protective structures for fishing activities, a daisy chain configuration with subsea satellite wells and Production Manifolds was selected for the Albacore field phase H development (Ref. 1). The Manifold original concept was developed by Petrobras and CBV Industria Mecanica. an FMC licensed company, was contracted to update that concept and to be the EPC (engineering, procurement and construction) leader for the project (Fig. 1) By selecting a Subsea Manifold for such an application, some challenges related to the deep water environment and the particular conditions of Brazil, can be mentioned:Manifold foundation - due to high costs associated to piling operations, the use of a shallow foundation appears to be the most practical solution;Vertical Connection System was to be proved as a cost effective and reliable method of connecting flexible flowlines to a subsea Manifold, particularly in such deep water:Hydraulically Actuated Gate Valves and Chokes are used in a Retrievable Valve Module configuration;Multiplex Control System is the most practical way of controlling all Manifold isolation valves plus the valves on the Satellite Trees, Due to the water depth, a guidelineless system needed to be developed;